Barstool Aerodynamics

I see a Corvette in the background, so you are up against some stiff competition.

Also, resist the urge to drink and drive, but solving the world problems while seated and rubbing elbows with your neighbor is perfectly fine.

To the extent possible minimize frontal surface area, especially of the pilot. (bent at the waist, legs together, arms in tight) For low drag shapes and surfaces look at NACA foils and speed skiing. And post photos so we can follow your progress. Good luck!

"the driver must sit down."

Does the driver have to face the direction of travel?

It says ONE motor, ONE battery...doesn't mention that you CAN'T have an Ultra Capacitor in the circuit!

It doesn't say that you even need a battery, just states maximum 12V DC power but also limited to one battery. So conceivably just a bunch of capacitors would be okay I think.

Holy cow, 54 MPH on a friggin' 12 volt powered bar stool!?! That's wild!

Are those the complete set of rules? It really does leave a lot open to interpretation, as some responses here have already mentioned.

Thats its. Those are the only rules. We are playin hookie and driving out to the flats this september to watch the races and do some "research".

So long as your butt is on the barstool, can you position yourself horizontally like a luge rider? How much distance is this race? I don't know if there are 12-volt forklift batteries, but that might be a way to go unless there is an amp-hour limitation. (Which might make sense.)

I don't think you can position yourself as a luge rider. I believe you must be upright with you legs underneath you. However from the youtube videos they are all crouched over with their legs tucked up as though they are sitting on their heels. Distance isn't to far, the typical runs I have seen are only about a minute or two and no am-hour limitation is stated in the rules.

This is a sweet project that sounds like it'll be alot of fun.

I come from a strong hydraulics background and here's my advice.... Review what you've learned about pressure drag and skin/body drag... set your focus on reducing BOTH (i.e. the total drag), not just one.

We had a water channel available to us at my school. It allowed us to do some quick models and test them, make adjustments, retest.... You might look into that, it makes the design process a little more fun.

Best of luck!

Given there is no such thing as a 12 volt battery, it would appear you can make up your own.

So instead of using 6 x 2 nominal volt lead acid cells in series, why not build a LION version? Quite a bit lighter, wet cells are capable of massive discharge rates, call them 3 volts nominal, package 4, say 200 Ah each and you have around 14.4 volts to play with.

Then you just need a motor that takes more than a minute, or so, to melt.

& I would put the rider fairly forward and avoid breaking. I don't think windage at the speeds involved is that big a deal compared to compromising power to weight ratio.

Smallest lightest rider tucked up, is probably as good as you'll practically get within the dimension limitations. See jockeys

34point5,

What do you mean "there is no such thing"? I believe that six cells in series of 2V each is a 12 V battery.

I agree that there are benefits to a LION battery, but calling a 3.7V cell a 3.0V cell does not make it so.

Actually when new they are 2.1, but I was asking myself the same question

Fredski,

I am not saying that you are wrong, but Lithium Ion cell voltage depends on the electrodes.

http://en.wikipedia.org/wiki/Lithium_ion#Electrochemistry

I was referring to lead acid, 6 cells each. Either way I think you knew what I meant.

Sorry, I did not. It was an honest mistake. Thanks for the clarification.

Your belief is correct - if there is more than 1, it's a battery

My point was/is about 'limits on thinking' common perception/usage inflicts.

Battery

6. Electricity

a. Two or more connected cells that produce a direct current by converting chemical energy to electrical energy.

b. A single cell, such as a dry cell, that produces an electric current.

Battery definition b. is technically wrong and there because of common usage, which extends to the perception of a 'battery' as a 'single thing'. Such as the 12 V package made for cars, or some such.

Locked to this 12 V single 'thing' approach, is 'lead boots' thinking.

Battery definition a. is the one that should apply to the 'power pack' design approach.

Hence 'make your own battery of cells' at "12 nominal volts" - meaning some point on the discharge curve - but ideally not exceeding the voltage reading of a fully charged lead acid - also called "12 volts", but is not - may result in somewhat 'freer thinking'.

I think people got too wrapped up in the details to take note of the point that a 12V LION would be ALOT lighter compared to a lead acid. (GA btw, it'll probably have more of an effect than any aerodynamic consideration)

Given the high seat and the short wheelbase, a heavy battery for ballast may be an asset. Finding a high-amperage battery for a short run is not too big a challenge, and there are probably a few in the catalogs that are 12V in one case, but too big for manual handling. "One 12V" motor also seems to leave a lot of room for big hardware.

The winning formula is probably a lead sled with a very streamlined wing section around the rider. This is one application where you can probably get extensive true laminar flow if you have someone lower a fairing over the whole vehicle. It will only be interrupted in a 15 deg spread from the front wheel openings. A NACA-66-025 shape for the top would probably serve well. A small, limber rider will probably be an asset, too. Unfortunately, with a laminar-flow enclosure, they can't sit up to provide braking and improve balance for wheel brakes.

Judging from the responses here, think your competition just widened!

Just for fun : http://www.legendarymotorcar.com/site/12033_1966_Shelby_GT350H

Do let us know your results...

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Prevent zagging - shortest distance between two points.....

Check out the lawnmower record holders for ideas.

This infinitely variable transmission has the gearing range of an 11-speed automotive transmission.and it looks small enough to fit in your barstool! I bet you can break all records with that puppy and a starter motor.

It clearly states in the rules...no gear boxes.